i have an eglu cube for my girls (5 bantams) and have seen teh up coming long range forecast which suggests its going to drop to -10 or there abouts by the end of november. will the cube be warm enough on its own or do i need to add extra insulation? the insulated cover on the eglu site says you need a run as well (presumably for attachment purposes) but i have a free standing cube so that then rules that out. chicks are about 6 - 8 months old and have just started laying (sooo proud!!).